Electric welding-machine.



No. 896,218. PATEN TED AUG. 18, 1908.

L. S. LACIIMAN. ELECTRIC WELDING MACHINE.

'LED

van VMWMMMI h RENEWED NOV. 22, 1907 LAURENCE S. LAOHMAN, OF NEW YORK, N.Y.

ELECTRIC WELDING-MACHINE.

Specification of Letters Patent.

Patented Aug. 18, 1908.

Application filed August 6, 1906, Serial No. 329,319. Renewed November22, 1907. Serial No; 403,340.

To all whom it may concern:

Be it known that I, LAURENCE S. LAoH- .MAN, a citizen of the UnitedStates, and resident of the borough of Manhattan, city, county, andState of New York, have invented certain new and useful Improvements inElectric Welding-Machines, of which the following is a specification,accompanied by drawings.

This invention relates to electric welding machines, more particularlyto the electrodes therefor, and the objects of the invention are toenable sheet metal plates or metal of other forms to be welded togetherat a multiplicity of points by autogenous union.

Further objects of the invention will hereinafter appear and to theseends the invention consists of an electric welding machine for carryingout the above objects embodying the features of construction,combinations of elements, and arrangement of parts having the generalmode of operation sub-' stantially as hereinafter fully described and asclaimed in this specification and as shown in the accompanying drawings,in which,

Figure 1 is a side elevation, partly in section of apparatus embodyingthe invention; Fig. 2 is an enlarged detail vertical sectional viewshowing an alternative construction of electrodes; Fi s. 3, 4, 5 and 6are enlarged detail sectional e evations showing further alternativeforms of electrodes; Fig. 7 shows a face view and Fig. 8 a sectionalelevation on the line 88 of Fig. 7 of a further alternative form ofelectrode; Fig. 9 is a face view and Fig. 10 a sectional elevation online 10-10 of Fig. 9 of a further alternative form of electrode; Fig. 11is a side elevation partly in section of another form of apparatus; andFig. 12 is a side elevation partly in section of the apparatus shown inFig. 11 in another position.

Referring to the drawings, A represents the frame of the machine of anysuitable character, preferably of metal, provided with the lowerelectrode B, which has a broad flat face C, on which the material to bewelded is placed. In this instance two sheets of metal are shown inposition for welding. The upper electrode E ma be of any desired shapein cross-section, in. this instance being shown cylindrical and as shownis provided with a flat face or surface F having a projecting portion orprotuberance G extending beyond the plane of the surface F and ofsmaller area than said surface. As shown, in Fig. '1 the projection G inface view is circular and is provided with a curved. surface, forming acontact button, although the shape of the projection G may be varied ifdesired.

The electrode E is preferably insulated from the frame A, as by a layerof insulating material, y and provided with means for forcing it towardsthe electrode B, being separated and insulated from the pressure-ap- Iplying means, as by interposed layer of insuating material 2. Anysuitable means may be provided for this urpose, as shown, there being anoperating ever H pivoted to the frame and rovided with a handle 1.. Theelectrode is pivoted to the lever H by means of the in J in the slot K.The electrodes B and are connected in a circuit of a suitable source ofcurrent shown as a dynamo L, and a switch 0 is rovided for connectingand disconnecting t e dynamo.

The flat sheets D are placed upon the electrode B, the switch 0 closed,and the electrode E is forced into contact with the lates. The contactprojection or button first bears upon the upper plate D, at which pointthere wlll be high resistance, and the current passing through theelectrodes and the plates will serve to highly heat the metal of theplates over a small area. At first the resistance is relatively hi howing to the fact that at first only relative y a small portion ofrotuberance G is in contact with up er p ate D, due to customary surfaceirregu arities of the plate and electrode, and when said protuberance isrounded as shown in Fig. 1,.

plates D is thereforev very rapid in the extremely localized regionbetween the electrodes. As the plates become softened the pressureapplied upon handle I forces the protuberance G into the upper plate,thereby improving the contact between the rotuberance G and the upperplate D an also imroving the contact between the two plates and betweenthe lower plate D and the low electrode 0, all in the localized regionvided with a button or projection G projectcorresponding to the contactarea of protuberance G. The pressure thus produced and the heatinginzthe extremely localized region mentioned, cooperate to produce aperfect welding of the two plates D in this localized region.- At aboutthe time when this welding is complete the meta will have become sosoftened that the protuberance G will have sunk into the metal to itsfull depth, bringing the larger plane surface F of electrode E intocontact with upper plate D, the effect of which is to greatly widen thearea through Which the electric current passes, and, there fore, togreatly decrease the effective heating action of the current so thatonce the weld is completed the current is diffused through a largerportion of the plates D and over-heating or detrimental heating of thelates reeluded. The plane surface F of eIectro e E further serves as apressing surface which, in

conjunction with the end of electrode D,-

serves to confine and even compress the softened and possibly fused orsemi-fused metal at and in the immediate vicinity of the point ofwelding, thus preventing deterioration of the quality of the metal atthis point, preventing the formation of a bur, and insuring a smoothunion. Furthermore, the pressure of the electrodes or dies exerted inthis manner prevents buckling, bending or distortion of the plates.

Metal plates about to be welded, unless carefully dried, usually havemore or less of a layer of adhering moisture. This moisture isimprisoned between the plates when they are p aced together and, beingvaporized suddenly by the intenseheat produced by the welding current,the steam tends to force the plates apart somewhat. This tendency dies Eand D repress by the pressure they exert, insuring that the plates shallbe welded to gether closely with their surfaces adjacent to the weld incontact. In hand operating a paratus such as described the upper electroe will then be withdrawn to break the circuit, but any suitable form ofautomatic circuit breaking apparatus may be provided, which will comeinto operation upon the increase of the current due to the decrease ofresistance when the face F of the electrode bears upon the plate D.After the operations are completed, the plates will be joined by a spotweld at the point at which the operations have been conducted, and thisoperation,

may be continued at as many different points as desired. The plate whichhas been in con tact with the button G will be slightly depressed at thepoint of weld.

In Fig. 2, each electrode P and Q is proing beyond the fiat surface F,and the p ates D are laid between the electrodes. In this instance thebuttons G first contact with the acacia plates, and after the operationis completed there will be a slight de ression in each plate at thepoint of the weld.

In Fig. 3, one electrode R is provided with a depression T, with whichthe button or projection G on the other electrode S cooperates. Theheight of the projection or contact button G should be slightly greater,as shown in Fig. 3, than the depth of the depression T, so that intimatecontact may be made between the metal of the plates D and the electrodesbetween the projection G and the depression T.

' In Fig. 4: the projection U on electrode V is in the form of acircular ridge adapted to cooperate with the circular depression W inthe .electrode X, illustrating another form of the projection anddepression in the electrodes.

In Fig. 5, each electrode a is provided with a circular ridge 7),between which the plates D are placed. In Fig. 6 only one of theelectrodes is provided with the circular ridge 6, the other electrode 0having a flat surface. In Figs. 4, 5 and 6 the form of the weldcorresponds to the outline of the projecting portion on one electrode,that is, each weld is in the form of a ring. The outline of theprojecting ridges ma be varied as desired.

In Figs. 7 an 8, one electrode d is provided with ridges (2, while theother electrode f is provided with depressions or recesses g which fallopposite the ridges e and the welds are formed along the line of theridges.

In Figs. 9 and 10 each electrode d is provided with cooperating ridges ewhich fall opposite each other, along which the welds are formed.

In the form of apparatus shown in Fig. 1 1, the upper electrode h isprovided with a movable central portion 11 adapted to project beyond thesurface of the electrode. The projecting contact portion '5 in thisinstance is shown springactuated, although any other suitable form ofelastic means may be used. The coil spring 7c is arranged behind theportion '11 and normally tends to force said portion outwardly. Meansare provided for varying the compression of the springs it, as by meansof the plunger Z having the plunger rod 0, which extends throu h theupper portion of the electrode h, an is provided with adjusting nuts p.In this instance toggle acting means q are provided for forcing theelectrodes together. When the toggle is broken the electrode h is movedaway from the lower electrode B. When the toggle isforced outwardly toits fullest extent, the

contact with one of the plates D, then the toggle is forced down,finally bringing the surface 1' of electrode it into contact with theplate D. According to the other mode of operation the electrode h isforced into intimate contact with the plate D, as in Fig. 12 and lockedin this position. The current is then turned'on and as the metal softensat the point of contact underneath the portion '11, the pressure of thespring forces the contact portion 7', outwardly, thereby'forming a weld,and extra pressure upon the electrodes is not necessary. The weld isthus formed by continual pressure due to the spring 70.

Obviously some features of this invention may be used without others andthe invention may be embodied in widely varying forms,

Therefore, without limiting the invention to the devices shown anddescribed, and without enumerating e uivalents, I claim and desire toobtain by etters Patent the following: i

1. In a machine for welding sheet metals, a source of welding current, aspot-welding pole connected to said source of current and ofcross-sectional area large enough to give it rigidity while permittingthe development of a welding heat therein, a fiat-faced surrounding bodyof metal, also connected to said source of current, and means forpressing said pole into a body of sheet metal a predetermmed distanceand bringing the flat face into contact with the sheet metal after saidpole has penetrated the predetermined distance.

2. In a machine for welding sheet metals, a source of welding current,an electrode connected to said source and having a broad flat contactface provided with a welding protuberance rising from and surrounded bysaid fiat face and having cross-sectionalmrea large enough to give itrigidity while permitting the development of a welding heat, said fiatface havin sufficient superficial .area surrounding sai protuberance toconfine the softened or fluid metal formed by it in welding, and meansfor pressing said protuberance into a body of sheet metal apredetermined distance and bringing the fiat surroundin surface intocontact with the sheet metal a ter the protuberance has penetrated 1 thepredetermined distance.

3. In a machine for weldin sheet metals,

a welding electrode havin a road fiat contact face and rovided wit oneor more relatively low iso ated welding protuberances of relatively widelateral extension, projecting from suchfiat contact face and spaced awayfrom its margins to give a substantial surrounding area of such fiatcontact face.

4. A welding machine comprising a pair of opposing electrodes, one orboth of said electrodes being provided with a substantially plane facehaving a low wide rotuberance arising therefrom and centrally ocatedthereon with a wide surrounding area of such plane face, and means forforcing said electrodes together. i

5. A welding machine comprising a pair of combined welding electrodesand press dies, one or both of said electrodes being provided with awhich 1s greater than its height, said protuberance rising from andsurrounded by a plane surface on the end of said electrode, of greaterarea than the area of cross-section of said protuberance, such planesurface serving as a pressure and contact surface to press against andconfine the metal surrounding the point of weld, and also serving todifluse the current after the weld is complete, and means for forcingsaid electrodes together.

6. In a welding machine, an electrode having an initial contact portionof relatively small cross-sectional area and in proximity thereto acurrent-diffusin flat-surfaced contact portion of relatively arger areastepped back from the initial contact portion and surrounding the sameconstructed to make contact with the surfaces to be acted on aftercompletion of the weld.

7. In an electric welding machine, the combination of two electrodesadapted to make contact with the material to be treated, at least one ofsaid electrodes having a portion of its contacting face movable wlthregard to the residue of said face and means for exerting elasticpressure behind said portion.

8. In T an electric welding machine, the combination of two electrodesadapted to make contact with the material to be treated, at least one ofsaid electrodes having a portion of its contacting face movable wlthregard to the residue of said face, means for exerting elastic pressurebehind said portion and means for forcing gether.

9. In an electric welding machine, the combination of two metallicelectrodes having fiat surfaces adapted to be pressed into contact withthe material to be welded, at least one of said electrodes having acentral spring pressed metal contact portion normally projecting beyondthe face of the electrode, and adapted to make contact first over arelatively small area on the material to be welded.

10. In an electric weldin machine, the combination of two metallic eectrodes adapted to make contact with the material to be welded at theoint of welding and having fiat faces arrange opposite each other, oneof said electrodes being provided with a portion projecting from itsface and adapted to make rotuberance one lateral dimension of I saidelectrodes toa: 1 eae ',21e

contact withithe material to be welded over In testimony whereof I havesigned this a relatively small area, thereby producing a specificationin the presence of two subscrib- 10 high reisistince, gaitd initial(fzlontact bfeirlllg ing Witnesses.

a apte to ema e eforet e atfaceo t e electrode comes into contact withthe mate- LAURENCE A rial, and means for forcing said electrodes to-Witnesses:

gether to cause the flat faces to come into E. VAN ZANDT, contact withthe material. I A. L. OBRIEN.

